Using innovative qualitative and quantitative methodologies, the Patient-Reported Outcomes Measurement Information System (PROMIS) initiative has developed high quality and clinically relevant patient-reported outcomes measures to be used to evaluate the impact of both disease and interventions on patients' lives. This study will add new knowledge of the reliability, validity, and responsiveness of PROMIS measures through an extensive psychometric evaluation within a population-based cohort of men with prostate cancer participating in a prospective comparative effectiveness research (CER) study. This includes a test of measurement equivalence across race, education, and age groups, as well as mode of administration of the PROMIS measures: via phone interviewer versus computer self-administered questionnaire. This evaluation will also include recently developed PROMIS domains including Sexual Function, Psychosocial Illness Impact, Sleep Related Impairment, and Gastro-Intestinal Symptoms - which are relevant for prostate cancer patients. In response to an Institute of Medicine report that indicated CER of prostate cancer treatments as a top 100 priority, the University of North Carolina was awarded a grant from the Agency for Healthcare Research Quality to conduct a prospective study. The North Carolina Prostate cancer Comparative Effectiveness & Survivorship Study is a population-based cohort of 1,400 prostate cancer patients with diverse race, education and age levels. Participants provide patient-reported data through phone interviews on their health-related quality of life (HRQOL) pretreatment, and at 3, 12, and 24 months post-treatment. These time points are critical as multiple studies have documented that many symptoms (i.e., sex, urinary, and bowel dysfunction; also fatigue, depression, anxiety) increase significantly from pretreatment to post-treatment, and then partially recover by 12 and 24 months. This trend provides an excellent opportunity to evaluate the responsiveness and to estimate minimally important differences of the PROMIS measures. The specific aims include: Aim 1: Evaluate the measurement properties of the PROMIS measures using item response theory models and other psychometric methods. Aim 2: Evaluate the ability of PROMIS measures to detect differences in health-related quality of life across age groups, race groups, treatment types, and comorbidity status. Aim 3: Evaluate the responsiveness of the PROMIS measures relative to legacy measures to detect clinically meaningful changes from baseline (pretreatment) through two years post-treatment. Aim 4: Test for measurement equivalence for the PROMIS measures for key prostate cancer subgroups including race, education, and age. Aim 5: Evaluate measurement equivalence across assessment modes of phone interview and computer self-administered survey. The multi-disciplinary team has extensive experience in psychometrics and prostate cancer care and research. Study results will significantly inform both the use of PROMIS in prostate cancer and provide key validation data on the PROMIS measures. PUBLIC HEALTH STATEMENT: Using innovative qualitative and quantitative methodologies, the NIH Patient-Reported Outcomes Measurement Information System(r) (PROMIS(r)) initiative has developed high quality and clinically relevant patient-reported measures to be used to evaluate the impact of both disease and interventions on patients' lives. This study will add new knowledge of the reliability, validity, and responsiveness of PROMIS measures through an extensive psychometric evaluation within a population-based cohort of men with prostate cancer participating in a prospective comparative effectiveness research (CER) study. Study results will provide key validation data on the PROMIS measures and will inform the adoption of PROMIS measures in prostate cancer CER and outcomes research.